Section 35
Chapter 34,403

Analysis of sugar and potassium contents in individual parenchyma cells of fruit using microdroplet of cell sap extracted by a micropipette method

Yonemori, K.; Kawabata, K.; Sugiura, A.

HortScience 36(3): 603


ISSN/ISBN: 0018-5345
Accession: 034402518

In order to estimate sugar and potassium concentrations in each cell of fruit, vacuolar saps from individual parenchyma cells of grape berry 'Neo Muscat' and persimmon fruit 'Hiratanenashi' were extracted at maturity by a micropipette in a micromanipulator system, using 300 mum sections of fresh berry/fruit prepared by a DSK-1000 microslicer (Dosaka EM, Kyoto, Japan). The concentration of each sugar in individual cell sap was measured using a fluorescence microscope equipped with a photometer by the intensity of fluorescence of NADPH after an enzymatic reaction of glucose, fructose, or sucrose in microdroplet of the sap was performed. The concentration of potassium was measured by X-ray microanalysis using a scanning electron microscopy (S-2150, Hitachi Ltd., Tokyo, Japan) equipped with a model EMAX-2770 analyser (Horiba Ltd., Kyoto, Japan) after the microdroplet of the same sap was dried. Measurements of 30 parenchyma cells of 'Neo Muscat' berry showed a small standard deviation for each sugar concentration, i.e. 407 +- 43 mM in glucose, 387 +- 37 mM in fructose, and 75 +- 16 mM in sucrose, indicating a relatively high uniformity of sugar accumulation among parenchyma cells of the grape. In contrast, 30 parenchyma cells of 'Hiratanenashi' fruit showed a high value of the standard deviation for each sugar content, i.e. 255+-128 mM in glucose, 133+-78 mM in fructose, and 124+-92 mM in sucrose, indicating inequality of sugar accumulation among the cells in persimmon. As for the potassium concentration in the parenchyma cells, both 'Neo Muscat' grape and 'Hiratanenashi' persimmon showed variable amounts among the cells. The homogeneity and heterogeneity of the parenchyma cells in sugar accumulation are discussed.

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